1. Field of the Invention
The present invention relates to a method for overwriting data of a rewritable optical disk quickly without physical erasing operation.
2. Description of the Related Art
In general, a disk drive, which writes/reads data to/from a rewritable disk such as CD-R/W, is used as connected with a host such as a personal computer (PC). Therefore, a disk drive receives data to write from a host, and sends reproduced data to it.
A disk drive conducting these writing/reading operations is configured as FIG. 1. The disk drive of FIG. 1 comprises an optical pickup 2 for writing/reading data to/from a rewritable disk 1, for example, a CD-R/W, an R/F unit 3 for equalizing and shaping RF signals reproduced by the optical pickup 2 to produce binary signals, a digital reproduced signal processing unit 4 for processing the binary signals from the R/F unit 3 to restore original digital data, an interface 5 for transmitting the restored digital data to a connected PC 200 and receiving data and commands from the PC 200, a digital recording signal processing unit 6 for converting the data received through the interface 5 to writing signals suitable for an optical disk, a servo and drive unit 7 for adjusting rotation speed of the rewritable disk 1 and moving writing/reading position on the disk 1, and a microcomputer 8 for supervising overall operation for conducting an entered key command from a user or a requested command from the PC 200.
FIG. 2 is a procedure conducted in the disk drive 100 configured as FIG. 1 when data overwriting is requested for a data-contained rewritable disk 1.
Explaining the procedure depicted in FIG. 2, when the rewritable disk 1 is inserted in the disk drive 100 (S10), the microcomputer 8 reads out disk information from the rewritable disk 1 (S12). The disk information consists of data written in Program Memory Area (PMA) and Table Of Contents (TOC) in which navigation data for all recorded tracks are included.
If the rewritable disk 1 is CD-R/W, the PMA, located next to most inward Power Calibration Area (PCA) as shown in FIG. 3, has record information for all recorded tracks, and the TOC, written in Lead-In Area (LIA) located at the head of each session, has all information about each corresponding session.
Therefore, to read out the disk information, the microcomputer 8 searches the rewritable disk 1 for the PMA and the first TOC, first of all. After reading the disk information, the microcomputer 8 checks disk type and record status (S14) based on the read disk information, then, it transmits the checked disk type and record status to the PC 200 (S16) connected through the interface 5 as well as stores them locally. An Operating System (OS) running in the PC 200 stores the received information from the disk drive 100 in device management information.
If the inserted rewritable disk 1 has useless data in it, a user should make the disk 1 blank, that is, erase all data at first to write new data in the disk 1. If writing of new data is requested without data deletion, since the OS has already known the disk information stored in the device management information, it compares the size of new data with remaining storage capacity of the rewritable disk 1, which is included in the disk information, then, it requests the disk drive 100 to write the new data only if the size of new data is smaller than the remaining capacity, otherwise, it does not request. In case that the remaining capacity can accommodate the new data, the disk drive 100 writes the new data from the start of blank program area, namely, after the useless data written in the disk 1 because it is aware of current record status. As a result, the useless data still remains after new data is recorded.
In the meantime, if the disk drive 200 receives a command of ‘disk erase’ (S20), it checks the erasing type, namely, that is ‘full’ or ‘quick’. If the type is ‘full’, the disk drive 200 makes a beam, whose power is set for data deletion, incident to whole disk area data have been written in, and if ‘quick’ it makes the erasing-power beam incident only to disk information area, i.e., PMA and each LIA to delete only disk information. FIG. 4 shows the erasing-power compared with reading and writing power. According to this erasing operation, the inserted disk becomes ‘blank’, so that the disk drive 200 reports the ‘blank’ status to the PC 200 (S22).
After receiving the ‘blank’ status from the disk drive 100, the OS of the PC 200 updates the device management information to reflect the ‘blank’ status of the inserted disk. Afterward, if new data is requested to be written, the OS checks whether the size of new data is smaller than the full storage capacity of the blank disk. If then, the OS requests the disk drive 100 to write the new data.
If the writing request is received (S24), the disk drive 100 writes the new data from the start of data zone of the rewritable disk 1 (S26) because the disk 1 has been made blank.
However, in the above data writing method, the necessary disk erasing operation takes long time even if its type is ‘quick’ needless to say ‘full’-type erasing, which causes a user inconvenience of waiting too much to re-use a data-contained rewritable disk.